A calcium channel complex in the mitochondrial inner membrane capable of highly-selective calcium channel activity. Its components include the EF-hand-containing proteins mitochondrial calcium uptake 1 (MICU1) and MICU2, the pore-forming subunit mitochondrial calcium uniporter (MCU) and its paralog MCUb, and the MCU regulator EMRE.
Catalysis of the reaction: 2 3-acyl-sn-glycero-1-phospho-(1'-sn-glycerol) = 3-acyl-sn-glycero-1-phospho-(3'-acyl-1'-sn-glycerol) + sn-glycero-1-phospho-(1'-sn-glycerol).
Catalysis of the synthesis of the HKK-1 carbohydrate epitope; adds a sulfate group to a precursor, GlcA-beta-(1->3)-Gal-beta-(1->4)-GlcNAc-beta-(1->R), forming sulfo-3GlcA-beta-(1->3)-Gal-beta-(1->4)-GlcNAc-beta-(1->R).